[#BOO-366] Remove one level of indirection from generators and allow generator methods to use IEnumerator as the return type

Boo

Remove one level of indirection from generators and allow generator methods to use IEnumerator as the return type

Created: 22/Jun/05 09:15 AM Updated: 22/Sep/05 02:50 PM

Component/s:

Compiler

Affects Version/s:

0.5

Fix Version/s:

0.7

Time Tracking:

Not Specified

Description

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Today is not possible to use yield to implement IEnumerable.GetEnumerator() because generators must be declared as returning IEnumerable.

Another problem is that we always have one level of indirection from the enumerator which makes very hard to consume a generator() incrementally like:

generator = { yield 1; yield 2 }
e = generator()
item, = e
assert 1 == item
item, = e
assert 2 == item

generator exhausted here

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Sorin Ionescu added a comment - 07/Aug/05 10:26 PM

Please cast the generators to the interface in question before you return them.
Seeing __________generator1 is not pretty; we shouldn't have to type "GetEnumerator() as IEnumerator" to get around that.

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Rodrigo B. de Oliveira added a comment - 08/Aug/05 04:33 AM

If the method in question belongs to an implemented interface its return type will be preserved.

The anonymous types are necessary to preserve type informaiton.

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Rodrigo B. de Oliveira added a comment - 22/Sep/05 02:50 PM

I didn't remove the level of indirection but simply allowed generator methods to declare their return type as IEnumerator directly. This has the advantage of not breaking any code while still allowing to easily implement IEnumerable.GetEnumerator.